The present invention refers to a marker of the type used in marking plastic parts, during the forming process thereof, in the core of an injection or blowing mould.
The object of the invention is to enhance the marking capacity thereof, specifically to increase the number of variables the marker may mark with maximum operational capacity.
When manufacturing a plastic part in a moulding process, it is normal to establish in the same, different types of references of a variable character, like, for example, the part moulding date, specifically determining the month and year when the part was manufactured.
Current markers have a fixed body, conveniently fitted in a mould housing, said fixed body adopting a tubular configuration, such that in the core thereof, there is a mobile nucleus, capable of varying its angular position with respect to the fixed body. In the aforementioned example of practical use, the use of the marker as a date marker, in the front of the fixed body the reliefs or bas-reliefs corresponding to the months of the year are established, in circumferential alignment and in the mobile nucleus, besides establishing a marking arrow for one of said months, the relief or bas-relief corresponding to the year.
This means that each year the marker should be released from the mould, to eliminate the mobile nucleus and replace it by another suitable one for the new year.
The marker proposed by the invention satisfactorily resolves this problem permitting, in the aforementioned case, its use for a long period of time, like for example, ten years, without the need to replace any of the parts.
For this purpose and more specifically, the marker consists of three basic parts, an annular, enveloping body that is fixed in the corresponding location of the mould, an annular rotational and intermediate body and a central core which is also mobile and rotational.
According to this structure and in the aforementioned example of practical embodiment, in the front of the central core, there will be, for example, a signalling arrow, in the front of the annular and rotational body, the months of the year and a second indicating arrow and on the fixed and enveloping body, a series of successive years, such that by the suitable, relative positioning between the three parts integrating the marker, any month of any of the years appearing on the enveloping body may be signalled.
According to another feature of the invention and to facilitate both the stability of the mobile parts in the position selected for them, and to facilitate handling of the marker, it has been foreseen that between the enveloping and intermediate bodies, there is a helicoidal spring and between the intermediate body and the central core, a second helicoidal spring, the first fixed by means of one of its ends to a cover closing the fixed and enveloping body at its end opposite the marker itself, and which constitutes the single activation component of the marker, and the second to the intermediate annular body, with the special feature that said springs have opposite winding directions, such that when they act over the cover-control in a determined rotation direction, one of the springs tends to be strangled over the intermediate body, provoking the dragging thereof, whilst the other one tends to be radially expanded, becoming inoperative with respect to the central core, such that when it acts over said cover-control in an opposite direction, the effect is also opposite, producing the dragging of the central axle or body and maintaining the intermediate rotational body static. Therefore, by means of the rotation of the cover-control in one direction, the signalling of the month is obtained and the signalling of the year is obtained by means of the rotation of the opposite sign.